The present invention relates to a differential apparatus including a clutch section for locking a differential motion between a pair of output members accommodated in a differential casing.
A differential apparatus of this type is disclosed in JP-A-06-344783, and will be briefly described as below. The differential apparatus includes helical pinion gears that are accommodated in receiving holes of a differential casing and mesh with each other, helical side gears, respectively, mesh-connected to the helical pinion gears, a locking member (shift sleeve) having a spur gear selectively meshing with a splined portion on an outer periphery of a right boss of the differential casing, and with a locking gear on a flange of the right side gear, and an operating member (shift fork) that operatively moves the locking member to lock a differential motion.
With the differential apparatus constructed in this manner, a drive force from an engine is transmitted to the differential casing and differentially delivered and transmitted from the helical pinion gears that mesh with each other, to the side gears, respectively, meshing with the helical pinion gears, and the drive force rotates right and left drive wheels via right and left drive shafts (not shown), respectively, connected to the respective side gears. And, in the case where a vehicle encounters a bad road such as a muddy road, etc. and an excessive differential motion is imminently generated by a wheel-spin of only one of the wheels, the operating member is operated to shift the shift sleeve to have the spur gear meshing with the locking gear on the side gear to connect and lock the differential casing and the side gear together, whereby the differential motion is stopped to dissolve the wheel-spin of only one of wheels, thus enabling escape from the bad road.
However, since such conventional differential apparatus adopts a construction, in which the shift sleeve serving as an operating member meshes on its side toward the differential casing with a whole periphery of the splined portion but the spur gear meshes at one point on a circumference with the locking gear on the side gear, a burden on the locking gear and the spur gear is increased. Also, the locking portion and the operating member are arranged at the same diameter and so a dimension in the axial direction is liable to be increased.